Eyepiece for optical instruments.



XR ,r-f?. ,l f' No. 843,502. V PATLNTEDTBB.5y 1907. g 1 W. &A. G.THOMSON.

f BYBPIEGB FOR OPTICAL INSTRUMENTS.

APPLICATION FILED MAR. G, 1906- 'n "Frei I I'- l;

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WWA/:55555.- v /fvI//vTo/es WM www /W y/wmf @1% V 57%0775QW l Aff() neyentran #.YlLLiM THOMSON AND ARCHiBi-XLD THOMSON, OF PHILADELPHA,

PENNSYLVANIA, ASSIGNORS TO FOX OPi'OAL iileiillfAC'l'Ui-bl G PNY, OFPHILADELPHIA, PENNSYLVANIA/, A. CORPORTON OF JERSEY.

oon- NEW Specieaton oi' Letters atent.

Patented Feb. 5, 1907.

Application filed March 6, i906. Serial No, 304,519.

Be it known that we, WiLLIAM TnOnsoN and ARCHIBALD G. T HOMsON, Citizensof the Unite-cl `tates, residing inthe city and County ofFliilatielphia, State ot' Pennsylvania, have invented a certain new anduseful improve'- ment in eye pieces for optical instruments, el whichthe following is a specii'ieation.

Our invention relates to an improvement in eye pieces for opticalinstruments, and it is designed to be used in connection with retractinglenses, Whether sueh lenses loe mounted in an instrument suoli as anOptometei or rel'rac-toineter, or whether the lenses be supported in anyother inaimer.

The object of our invention is to "produeea device by the use of whichthe detect or ctel'eets iii the refraction ol" an eye may be ascertainedwithout the use of eert ain drugs, known as mytiriatics, which are usetito 'par alyze the oiliary muscle or aeeominodatiye power of the eye.

'lhis result is el'l'eeted by the employment oi' means which divides thelight which enters an eye, whieli may be under examination, l'roni asmall luminous spot of light into two parts or elements and which alsoacts unen the light so as to reduce its intensity to suoli an extentthat when striking or falling upon the retina, it (locs not oause anexcitation oli the ciliary muscle. The presence of a detect iii theretraction of an eye lia-ying been ascertiiiiieil, the amount or extentof suoli (lel'ieot may be measured by means oll lenses which may besupported in any desirable manner.

Our invention resides in the combination and arrangements of parts ashereinafter set l'orth in detail, sneci'lically -pointed out in theclaims, and as illustrated in the accompanying drawings, in w liicli,

Figure l is a plan view of our invention;

Figure 2 is a section on the lino 2-2 ot Figure 1;

`Figure 3 is a section on the lino 3-3 of Figure 1, looking to theright; and

Figure et is a section on the line 3-3 of Figure l lookingI to thelel't.

ln the drawings,

1 designates a plate provided with a central opening 2; 3 designates aholiler which surrounds the opening 2 and which is secured rllie to theplate l in any suitable manner. internal diameter Ol the holder 3 1sgreater than the diameter Ot' the opening 2, so that a narrow portionot' the material o1 the plate l surrounding the opening 2 is includedwithin the holder 3.

'llie 'plate l, Opening 2, and holder 3 are illustrated in the(iraw'ings as being circular, but tlieyneed net neoessarily be oi thisshape or contour. l

The essential feature oi our invention reites in the assooianon of meanswith a eylinder of giii'ss of lrgh curvature by the eniployment ofwhich, as heretofore "Pointed out, the etelbet in the reliraoton of aneye (it sueii etefeot exists) may be asoertainc In thetirawings, l haveilli "atei a semioiroular portion of rubyv or other oolorel glass 5 asbeingiissoo'fateit with a 'senilsoiroular ',oortion of a o y 'linger of'white glass (j having a high curvature. These portions Oiglass areloeate-t Withln the hoh Sentire" 'i i :on the portion of the material ol'Plate 1W h is inelufiei wit-inn the said holger. It'may be stateil herethat the liolter 3 is ein'oloyez merely as aprotection for the portionsof glass 5 anu 6, and, if ileslref't, suoli holfer may be oniittezl oranother iorm of he' er may be substitutef. The portions of' glass 5 ana(3 may be seeiiregi to the gelate l ni line with the Opening 2therethrough iii any tiesireii manner. The eolorett portion of glass 5consists ol: a "plate the ogrgosite sides or surlaocs of wheh areirallel.

In the construction illiistratefl by us, the portion of glass 6 consistsof a semi-eireular portion or section o'l' the segment olc a oylflii-(ler or roLl of white glass, anti in the particular en'ibo'tnnient ofour invention, as illustrateil. iii the drawings, each of the ees olglass 5 anzi 6 has one straight eige and in. the oonipleteiii devicesthcseefrges are arranged siile by sitle anii in Contact.

Our invention is to be regari'leih however, as ineluiting within itsseO,-;e any means assooiatei with a eylnxler of glass ol'v higheuryatiire by means of which the 'presence of ftei'eets in thercliraeton ol the eyes Ol a lxerson may be :'isoertainezl aiiil we (ionot desire or inteirl to limit ourselves to the details of eonstructionillustrz'itet.

By easoii of the fact that the portion of glass 5 is colorel anii itsOngi-osito laces or surfaces are parallel, anzl by reason of the l'aetthat the portion of glass (i is eurvetl upon IOO IOS

one side and in one direction only, it will be understood that a light,as for instance a small light of a candle, examined through the devicewill be divided into two parts, namely, a small spot of light having thesame color as that of the colored piece of glass 5 and a line i of lightoccasioned by the curved piece of glass (j. rIhe relative positions ofthese two portions of as examined by an observer depend upon thecondition of the eye of the observer.

In an einmetropic eye, the spot of colored ight will be found to bebisected by the line of white ifght. However, if the refraction of theeye of the observer is imperfect, the spot of colored lght will be toone side or the other of the line ot' white light, depending upon thenature ofthe defect in the eye. In a myopie eye, the spot is seen to thesame side of the line as the reti glass is to the cylinder when placedbefore the eye, while in h vperopia, the red spot is seen to the otherside of the white line.

IVhen either of these or similar conditions are noted, the line of whitelight and the spot of colored light will be brought into coincidence byinterposfng lens or lenses at certain points between the eye piece andthe spot of light which is being observed. The positions to which suchlenses must be moved vary accorr.: to the eye of the person loolting atthe light through the eyepiece.

By the use of these lenses to bring the spot of colored light and theline cf white light into coincidence, we are enabled to measure therefraction of an eye, after which the proper glasses may be prescribedfor the person whose eyes have been examined, in order to correct thedefect or defects cf vision.

I Iaving thus descrihed our invention, we claiml. A device of thecharacter described, comprising a plurality of pieces of glass arrangednear enough together to be simultaneously within the iield of vision cfan eye,

one of which pieces of glass is colored, and I the other of which is asection or portion of a segment of a cylinder er rod of white glass.

2. An eye picco for optical instruments, comprising a plurality ofpieces of glass, one of which pieces of glass has its opposite surlightwith respect to each other faces arranged in parallel relatay o .eaehother, and the other one of which 1s Vphine upon one side and the otherside of which is curved in one direction only, the said pieces of glassbeing arranged out of alinement so as to permit light to enter the eyethrough either of the said pieces of glass without passing through theother of said pieces.

3. A device of the character described, comprising a plurality of piecesof glass arranged sidc by side and in contact with each other, one ofwhich is colored, and the opposite surfaces of which are plane, and theother one of which is a section or portion of a segment of a cylinder orrod of white glass.

4. A device of the character described, comprising aplurality ofsemi-circular pieces of glass having straight edges which are arrangedin contact, one of the said pieces of glass being colored and having itsopposite surfaces parallel, and the other of said pieces of glass beinga section or portion of a segment of a cylinder of white glass.

5. In an eye piece for optical instruments, in combination, a platehaving a central open ing therein, and a plurality of semi-circularpieces of glass secured to the said plate in line with the said opening,one of the said .glasses being colored and having its opposlte surfacesparallel, and the other of said glasses being plano-convex 1n onedirection,

,each of the said pieces of glass having a traight edge, which edges arearranged in parallel relation to each other.

6. In a device of the character described, the combination of a cylinderof glass and means associated therewith for permitting light to enterthe eye without passing through the cylinder, whereby the presence ofdefects of .refraction of an eye may be ascertained\.\

In testimony that we claim the foregoing as our inventionL we havehereunto signed our names this ZQth day of February, A. D.

IVM. THOMSON, ARCHIBALD G. THOMSON.

In presence of- LEwIs nNKrNs, HARRY F. -AMBLER-

